Prion diseases are diseases of protein conformation which arise through the abnormal metabolism of the cellular prion protein (PrPc). We currently lack a detailed understanding the molecular level, of he mechanism by which the aberrant forms of PrP are derived from PrPc. Our approach has been to generate large and diverse panels of recombinant monoclonal antibodies to PrP by immunizing PrP-knockout mice with different PrP antigenic preparations and rescuing antibodies via phage display libraries. These novel antibodies have subsequently been employed as sensitive probes to generate a structural map of PrP conformation transition. To date, the antibodies have, together with protein engineering, structural and spectroscopic studies of PrP, begun to provide the first glimpses of conformation rearrangements involved in the acquisition of prion infectivity. Here, in pursuit of our ongoing goal to define events in the genesis of abnormal PrP isoforms, we propose to use antibodies to map the conformations of oligomeric forms of PrP since these oligomers likely form a structural link between PrPc and PrPSc. We will generate novel antibodies against oligomeric forms of PrP refolded to adopt both alpha-helical and beta-sheet conformations. We also aim to generate antibodies specifically recognizing unpurified oligomeric PrPSc as it occurs in infected tissues. Collectively this conformational information will be employed to identify key structural changes taking place as PrPSc is formed from PrPc. In addition, we propose to generate antibodies to the octapeptide repeat region of PrP, to examine conformational changes ensuing from the binding of copper-II-ions and to facilitate immunoaffinity purification of PrP106 and its derivatives.